1. Field of the Invention
This invention relates to an image processing apparatus and method, such as an adaptive-type image processing apparatus and method for executing image processing on the basis of results obtained by extracting the features of an image.
2. Description of the Related Art
Recent years have seen remarkable developments in color printing systems such as color printing apparatuses for digitally processing color image data and outputting the processed data to a color printer to obtain a color image, as well as so-called digital copiers for performing color image copying by subjecting a color original to color separation, reading the colors electrically and printing out the obtained color image data on recording paper. The growing popularity of these systems has been accompanied by the demand for a color-image printing quality that will allow black characters and fine lines to be printed sharply and darkly, as well as a demand for high-speed color output.
In order to meet the demand for higher speed, the single drum arrangement in which an original is scanned four times for the four separated colors M, C, Y, K is being replaced by a system using a four cascaded drums in which scanning of the original need be performed only one time. This system requires a large-capacity memory in which the signals representing the four colors are stored as is. However, since a large-capacity image memory raises the cost of the apparatus, it has been contemplated to reduce the required storage capacity by compressing the image signals before they are stored. It has also been attempted to reduce the required storage capacity by adopting pixel block units of a prescribed size for the storage of results of black-character discrimination, namely by lowering resolution. With this expedient, however, certain problems arise.
Specifically, in the case of a discrimination signal of the type which represents the possibility of a black character by multiple values, the number of bits that must be stored increases and, as a consequence, there is an increase in the amount of information to be stored, even if the results of black-character discrimination are stored in pixel block units. In particular, even if an image signal representing an original is compressed, as mentioned above, the required storage capacity of the overall system cannot be reduced sufficiently when it is attempted to store the results of black-character discrimination in the form of multiple values.